Epibulbar osseous choristoma: case report and review of the literature.

Epibulbar osseous choristoma is a choristomatous lesion of the conjunctiva containing bone. Originally called epibulbar osteoma, this lesion was first described by von Graefe in 1863. We discuss a case of a 4-year-old patient who presented with an epibulbar lesion consistent histopathologically with an epibulbar osseous choristoma, and report a review of the literature. The differential diagnosis of osseous choristoma should include classical limbal dermoids, epithelial inclusion cysts, prolapsed orbital fat, papillomas, dermolipomas, and complex choristomas. Although the rarest of epibulbar choristomas, 51 epibulbar osteomas have now been reported in the medical literature. Most commonly, this variety of choristoma presents as an isolated epibulbar lesion within the supratemporal quadrant but may occur in other locations on the surface of the globe and possibly in conjunction with other choristomatous tissue as much as 10% of the time. Frequently, they may involve the muscle or have dense attachments to the underlying sclera. Osseous choristomas most likely represent congenital lesions with a potential for slow growth but may occur in association with trauma. Options for management include observation or surgical excision. When surgery is contemplated, preoperative radiographic imaging may be helpful for assessing adhesion to the sclera or extraocular muscles.